Mission lifetimes of some integrated circuit (IC) devices can be predicted based on, e.g., theoretical, empirical or semi-empirical models of failure mechanisms. Failure mechanisms, in turn, depend on the type(s) of wear-out stress(es) that cause failure of the IC devices. Stresses that cause wear-out of the IC devices include thermal stress, voltage (or electromagnetic field) stress, current stress, and mechanical stress, among other types of stresses. Some failures are caused by acute stresses, e.g., an electrical overstress (EOS) or an electrostatic discharge (ESD) event, while other failures are caused by cumulative stresses, e.g., thermal, voltage or current stresses during operation. The IC devices that are subjected to these wear-out stresses beyond their predicted mission lifetimes can be subject to increased probability of reliability failures, which can be sudden and catastrophic. For example, certain thermally activated failure mechanisms, e.g., data retention of memory devices, have predictable time-to-fail at a given temperature. However, the stresses that cause wear-out can be intermittent and variable. As a result, it can be difficult to predict a time-to-fail even when the failure mechanisms are relatively well-known. Therefore, it is desirable to monitor cumulative stresses real-time, such that a user can monitor, e.g., automatically, how close to the end of the mission lifetime the IC device actually is, to avoid sudden failures.
One approach to monitor wear-out stresses may be to implement a sensor system. The sensor system can include one or more sensors, e.g., a temperature sensor and a current sensor, for measuring the stresses and the associated circuitry for converting the measured stresses. The measured values associated with the stresses can then be recorded and tracked for possible excursions outside a prescribed limit. Such monitoring can be performed over a lifetime of a product to alert the user of a predicted failure. However, there can be a number of restrictions for such a system. For example, the sensor system may include a power supply for continuous sensing over the lifetime of the product. In addition, the sensed signal, e.g., voltage or current signal, may be volatile and be lost if not stored. A wear-out level of a component being monitored may then be calculated from the stored information. As a result, a built-in memory and/or an ability to transmit information to an external memory may be implemented. Furthermore, the range of monitored conditions may be limited by the sensors themselves. For example, if the sensor is a semiconductor-based device, the range of temperature, voltage and/or current that can be monitored for the monitored component may be limited by the operating parameters of the semiconductor-based device. Outside of the range, excursions may not be monitored and recorded because of possible failures of the sensor system itself. Thus, there is a desire for improved wear-out monitor devices.